1. Field of the Invention
The present invention relates to an apparatus for dividing and combining electromagnetic energy. In particular, the present invention relates to an apparatus for dividing transverse electromagnetic waves into smaller signals, amplifying the smaller signals, and then recombining the amplified signals into a high power microwave source.
2. Description of Related Art
Communication systems require high levels of microwave energy to provide for high data rates and error free reception of signals. The prior art has attempted to satisfy these shortcomings using traveling waveguides, and more recently, solid state devices amplifying devices. However, existing solid state amplifying devices are not effective for producing high energy microwave source signals efficiently. Moreover, equipment capable of providing such high energy levels of microwave power is very expensive, requires excessive amounts of power, and has a short service life.
U.S. Pat. No. 4,091,334, issued to Sechi, discloses a circular waveguide that transitions into an array of radial slot lines coupled to amplification devices. While the device of Sechi may have low loss through the use of circular TE01 mode, the device requires the use of an oversized circular waveguide to convert from rectangular to circular modes. The oversized waveguide also produces the excitation of undesired modes that are difficult to remove. Thus, there is a need for a microwave amplifying device that does not excite undesired modes.
U.S. Pat. No. 4,272,740, issued to MacMaster et al., discloses a device comprising a cylindrical array of transmission lines and bars surrounding a central core. The bars have slots for producing parallel plate TEM modes. The device allows for several approaches for exciting fields in the slots; however, the complexity of manufacturing the device as well as the necessity of coupling either a waveguide or a coaxial line make the device of MacMaster unpractical. Moreover, the device of MacMaster also excites undesired modes.
Other techniques in the present state of the art are also demonstrated by U.S. Pat. Nos. 4,282,492; 4,291,278; 4,371,845; and 4,424,496. Additional techniques of power combining are disclosed in "Millimeter-Wave Power-Combining Techniques," IEEE Transactions on Microwave Theory, February 1983, pp. 91-107; "An X-Band Single Horn Autotrack Antenna Feed System," IEEE, 1991, pp. 86-89; "30-Way Radial Power Combiner for Miniature GaAs FET Power Amplifiers," IEEE MTT-S Digest, 1986, pp. 515-518; "An 19-Way Isolated Power Divider Via the TE.sub.01 Circular waveguide Mode Transition," IEEE MTT-S Digest, 1986, pp. 511-513; and "A K-Band GaAs FET Amplifier with 8.2-W Output Power" IEEE Transactions on Microwave Theory and Techniques, March 1984, pp. 317-324.
While the prior art provides several methods and devices for power dividing and combining, these methods are inefficient. The inefficiencies in power combining also limit the number of devices that may be combined and make them unsuitable for combining large numbers of devices. Additionally, the prior art devices are expensive and difficult to manufacture and fabricate. Thus, there is a need for an efficient microwave power divider/combiner that can be manufactured at low cost.